ASTM D1492-96(2000)

Designation: D 1492 – 96 (Reapproved 2000)
Standard Test Method for
Bromine Index of Aromatic Hydrocarbons by Coulometric
Titration
This standard is issued under the fixed designation D 1492; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope D 2710 Test Method for Bromine Index of Petroleum Hy-
drocarbons by Electrometric Titration
1.1 This test method covers the determination of the amount
D 3437 Practice for Sampling and Handling Liquid Cyclic
of bromine-reactive material in aromatic hydrocarbons. It is
Products
usually applied to materials having bromine indexes below
D 3505 Test Method for Density or Relative Density of
500.
Pure Liquid Chemicals
NOTE 1—Other test methods for determining bromine-reactive material
D 4052 Test Method for Density and Relative Density of
are Test Methods D 1159, D 1491, D 2710, and D 5776.
Liquids by Digital Density Meter
1.2 This test method has been found applicable to aromatic
D 5776 Test Method for Bromine Index of Aromatic Hy-
hydrocarbons containing no more than trace amounts of olefins
drocarbons by Electrometric Titration
and that are substantially free from material lighter than
E 29 Practice for Using Significant Digits in Test Data to
isobutane and have a distillation end point under 288°C.
Determine Conformance with Specifications
1.3 The following applies to all specified limits in this test
2.2 Other Document:
method: For purposes of determining conformance with this
OSHA Regulations, 29 CFR, paragraphs 1910.1000 and
test method, an observed value or a calculated value shall be
1910.1200
rounded off “to the nearest unit” in the last right-hand digit
3. Terminology
used in expressing the specification limit, in accordance with
the rounding-off method of Practice E 29.
3.1 Definition:
1.4 This standard does not purport to address all of the
3.1.1 bromine index—the number of milligrams of bromine
safety concerns, if any, associated with its use. It is the
consumed by 100 g of sample under given conditions.
responsibility of the user of this standard to establish appro-
4. Summary of Test Method
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. For a specific
4.1 The specimen is added to a solvent and titrated with
hazard statement see Section 8. electrolytically generated bromine at room temperature. The
end point is determined by a dead-stop method. The time of
2. Referenced Documents
titration is proportional to the bromine added to the specimen.
2.1 ASTM Standards:
5. Significance and Use
D 891 Test Methods for Specific Gravity, Apparent, of
Liquid Industrial Chemicals
5.1 This test method is useful for setting specification, for
D 1159 Test Method for Bromine Number of Petroleum use as an internal quality control tool, and for use in develop-
Distillates and Commercial Aliphatic Olefins by Electro-
ment or research work on industrial aromatic hydrocarbons and
metric Titration related materials. This test method gives a broad indication of
D 1193 Specification for Reagent Water
olefinic content. It will not differentiate between the types of
D 1491 Test Method for Bromine Index of Aromatic Hy- aliphatic unsaturation.
drocarbons by Potentiometric Titration
6. Apparatus
1 6.1 Amperometric-Coulometric Apparatus, automatic, suit-
This test method is under the jurisdiction of ASTM Committee D16 on
Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of able for bromine index titration’s with variable generator
Subcommittee D16.0E on Instrumental Analysis.
Current edition approved Dec. 10, 1996. Published February 1997. Originally
published as D 1492 – 57 T. Last previous edition D 1492 – 92. Annual Book of ASTM Standards, Vol 05.02.
2 7
Annual Book of ASTM Standards, Vol 15.05. Annual Book of ASTM Standards, Vol 06.04.
3 8
Annual Book of ASTM Standards, Vol 05.01. Annual Book of ASTM Standards, Vol 14.02.
4 9
Annual Book of ASTM Standards, Vol 11.01. Available from Superintendent of Documents, U.S. Government Printing
Office, Washington, DC 20402.
Discontinued; see 1985 Annual Book of ASTM Standards, Vol 06.03.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 1492
FIG. 1 Automatic Amperometric-Coulometric Titrator Circuit
current and timer. A typical circuit diagram of suitable equip- 7.3 Electrolyte—To make 1 L, mix 600 mL of glacial acetic
ment is shown in Fig. 1. acid, 260 mL of absolute methanol, and 140 mL of KBr
6.2 Syringe, 2 mL with needle and rubber cap seal. solution (119 g/L). Dissolve2gof Mercury II acetate in this
6.3 Stirrer, magnetic. mixture.
7.4 Potassium Bromide Solution (119 g/L)—Dissolve 119 g
7. Reagents
of potassium bromide (KBr) in water and dilute to 1 L.
7.1 Purity of Reagent—Reagent grade chemicals shall be
8. Hazards
used in all tests. Unless otherwise indicated, it is intended that
8.1 Consult current OSHA regulations, supplier’s Material
all reagents shall conform to the specifications of the Commit-
tee on Analytical Reagents of the American Chemical Society, Safety Data Sheets, and local regulations for all materials used
in this test method.
where such specifications are available. Other grades may be
used, provided it is first ascertained that the reagent is of
9. Sampling
sufficiently
...